Polyglycolic acid has high hydrolyzability as well as excellent gas barrier properties, heat resistance, and mechanical strength. Because of this, polyglycolic acid has been used as raw materials with low environmental load and as molding materials in various fields such as fiber and medical fields.
To obtain polyglycolic acid molded articles with high hydrolyzability and low environmental load, various methods, such as a method of adding a hydrolysis auxiliary agent to polyglycolic acid (Patent Document 1) and a method of subjecting a polyglycolic acid molded article to hydrothermal treatment (Patent Document 2), have been investigated. In these methods, hydrolyzability of polyglycolic acid molded articles is enhanced by selecting or controlling the molecular weight of the polyglycolic acid.
Meanwhile, in production of biodegradable aliphatic polyester molded articles, a method of controlling the molecular weight of the aliphatic polyester by irradiating with radiation such as an electron beam has been investigated.
For example, Patent Document 3 describes fibers formed from a biodegradable polymer that contains a biodegradable aliphatic polyester and polyfunctional triazine compound and that is obtained by crosslinking the aliphatic polyester and the polyfunctional triazine compound by irradiating with radiation.
Patent Document 4 describes a thermolysis-resistant polyester obtained by kneading a biodegradable aliphatic polyester and a polyfunctional monomer and then irradiating with radiation.
Patent Document 5 describes decomposition of a molded plate of polylactic acid having a thickness of 1 mm by using an enzyme liquid after irradiating the molded plate of polylactic acid with an electron beam.